mtd: rawnand: add NVIDIA Tegra NAND Flash controller driver
authorStefan Agner <stefan@agner.ch>
Sun, 24 Jun 2018 21:27:25 +0000 (23:27 +0200)
committerMiquel Raynal <miquel.raynal@bootlin.com>
Mon, 2 Jul 2018 07:02:06 +0000 (09:02 +0200)
Add support for the NAND flash controller found on NVIDIA
Tegra 2 SoCs. This implementation does not make use of the
command queue feature. Regular operations using ->exec_op()
use PIO mode for data transfers. Raw, ECC and OOB read/writes
make use of the DMA mode for data transfer.

Signed-off-by: Lucas Stach <dev@lynxeye.de>
Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
MAINTAINERS
drivers/mtd/nand/raw/Kconfig
drivers/mtd/nand/raw/Makefile
drivers/mtd/nand/raw/tegra_nand.c [new file with mode: 0644]

index 07d1576..63700ce 100644 (file)
@@ -14054,6 +14054,13 @@ M:     Laxman Dewangan <ldewangan@nvidia.com>
 S:     Supported
 F:     drivers/input/keyboard/tegra-kbc.c
 
+TEGRA NAND DRIVER
+M:     Stefan Agner <stefan@agner.ch>
+M:     Lucas Stach <dev@lynxeye.de>
+S:     Maintained
+F:     Documentation/devicetree/bindings/mtd/nvidia-tegra20-nand.txt
+F:     drivers/mtd/nand/raw/tegra_nand.c
+
 TEGRA PWM DRIVER
 M:     Thierry Reding <thierry.reding@gmail.com>
 S:     Supported
index 6871ff0..6074a94 100644 (file)
@@ -530,4 +530,14 @@ config MTD_NAND_MTK
          Enables support for NAND controller on MTK SoCs.
          This controller is found on mt27xx, mt81xx, mt65xx SoCs.
 
+config MTD_NAND_TEGRA
+       tristate "Support for NAND controller on NVIDIA Tegra"
+       depends on ARCH_TEGRA || COMPILE_TEST
+       help
+         Enables support for NAND flash controller on NVIDIA Tegra SoC.
+         The driver has been developed and tested on a Tegra 2 SoC. DMA
+         support, raw read/write page as well as HW ECC read/write page
+         is supported. Extra OOB bytes when using HW ECC are currently
+         not supported.
+
 endif # MTD_NAND
index 165b7ef..d5a5f98 100644 (file)
@@ -56,6 +56,7 @@ obj-$(CONFIG_MTD_NAND_HISI504)                += hisi504_nand.o
 obj-$(CONFIG_MTD_NAND_BRCMNAND)                += brcmnand/
 obj-$(CONFIG_MTD_NAND_QCOM)            += qcom_nandc.o
 obj-$(CONFIG_MTD_NAND_MTK)             += mtk_ecc.o mtk_nand.o
+obj-$(CONFIG_MTD_NAND_TEGRA)           += tegra_nand.o
 
 nand-objs := nand_base.o nand_bbt.o nand_timings.o nand_ids.o
 nand-objs += nand_amd.o
diff --git a/drivers/mtd/nand/raw/tegra_nand.c b/drivers/mtd/nand/raw/tegra_nand.c
new file mode 100644 (file)
index 0000000..9f7de36
--- /dev/null
@@ -0,0 +1,1230 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Stefan Agner <stefan@agner.ch>
+ * Copyright (C) 2014-2015 Lucas Stach <dev@lynxeye.de>
+ * Copyright (C) 2012 Avionic Design GmbH
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#define COMMAND                                        0x00
+#define   COMMAND_GO                           BIT(31)
+#define   COMMAND_CLE                          BIT(30)
+#define   COMMAND_ALE                          BIT(29)
+#define   COMMAND_PIO                          BIT(28)
+#define   COMMAND_TX                           BIT(27)
+#define   COMMAND_RX                           BIT(26)
+#define   COMMAND_SEC_CMD                      BIT(25)
+#define   COMMAND_AFT_DAT                      BIT(24)
+#define   COMMAND_TRANS_SIZE(size)             ((((size) - 1) & 0xf) << 20)
+#define   COMMAND_A_VALID                      BIT(19)
+#define   COMMAND_B_VALID                      BIT(18)
+#define   COMMAND_RD_STATUS_CHK                        BIT(17)
+#define   COMMAND_RBSY_CHK                     BIT(16)
+#define   COMMAND_CE(x)                                BIT(8 + ((x) & 0x7))
+#define   COMMAND_CLE_SIZE(size)               ((((size) - 1) & 0x3) << 4)
+#define   COMMAND_ALE_SIZE(size)               ((((size) - 1) & 0xf) << 0)
+
+#define STATUS                                 0x04
+
+#define ISR                                    0x08
+#define   ISR_CORRFAIL_ERR                     BIT(24)
+#define   ISR_UND                              BIT(7)
+#define   ISR_OVR                              BIT(6)
+#define   ISR_CMD_DONE                         BIT(5)
+#define   ISR_ECC_ERR                          BIT(4)
+
+#define IER                                    0x0c
+#define   IER_ERR_TRIG_VAL(x)                  (((x) & 0xf) << 16)
+#define   IER_UND                              BIT(7)
+#define   IER_OVR                              BIT(6)
+#define   IER_CMD_DONE                         BIT(5)
+#define   IER_ECC_ERR                          BIT(4)
+#define   IER_GIE                              BIT(0)
+
+#define CONFIG                                 0x10
+#define   CONFIG_HW_ECC                                BIT(31)
+#define   CONFIG_ECC_SEL                       BIT(30)
+#define   CONFIG_ERR_COR                       BIT(29)
+#define   CONFIG_PIPE_EN                       BIT(28)
+#define   CONFIG_TVAL_4                                (0 << 24)
+#define   CONFIG_TVAL_6                                (1 << 24)
+#define   CONFIG_TVAL_8                                (2 << 24)
+#define   CONFIG_SKIP_SPARE                    BIT(23)
+#define   CONFIG_BUS_WIDTH_16                  BIT(21)
+#define   CONFIG_COM_BSY                       BIT(20)
+#define   CONFIG_PS_256                                (0 << 16)
+#define   CONFIG_PS_512                                (1 << 16)
+#define   CONFIG_PS_1024                       (2 << 16)
+#define   CONFIG_PS_2048                       (3 << 16)
+#define   CONFIG_PS_4096                       (4 << 16)
+#define   CONFIG_SKIP_SPARE_SIZE_4             (0 << 14)
+#define   CONFIG_SKIP_SPARE_SIZE_8             (1 << 14)
+#define   CONFIG_SKIP_SPARE_SIZE_12            (2 << 14)
+#define   CONFIG_SKIP_SPARE_SIZE_16            (3 << 14)
+#define   CONFIG_TAG_BYTE_SIZE(x)                      ((x) & 0xff)
+
+#define TIMING_1                               0x14
+#define   TIMING_TRP_RESP(x)                   (((x) & 0xf) << 28)
+#define   TIMING_TWB(x)                                (((x) & 0xf) << 24)
+#define   TIMING_TCR_TAR_TRR(x)                        (((x) & 0xf) << 20)
+#define   TIMING_TWHR(x)                       (((x) & 0xf) << 16)
+#define   TIMING_TCS(x)                                (((x) & 0x3) << 14)
+#define   TIMING_TWH(x)                                (((x) & 0x3) << 12)
+#define   TIMING_TWP(x)                                (((x) & 0xf) <<  8)
+#define   TIMING_TRH(x)                                (((x) & 0x3) <<  4)
+#define   TIMING_TRP(x)                                (((x) & 0xf) <<  0)
+
+#define RESP                                   0x18
+
+#define TIMING_2                               0x1c
+#define   TIMING_TADL(x)                       ((x) & 0xf)
+
+#define CMD_REG1                               0x20
+#define CMD_REG2                               0x24
+#define ADDR_REG1                              0x28
+#define ADDR_REG2                              0x2c
+
+#define DMA_MST_CTRL                           0x30
+#define   DMA_MST_CTRL_GO                      BIT(31)
+#define   DMA_MST_CTRL_IN                      (0 << 30)
+#define   DMA_MST_CTRL_OUT                     BIT(30)
+#define   DMA_MST_CTRL_PERF_EN                 BIT(29)
+#define   DMA_MST_CTRL_IE_DONE                 BIT(28)
+#define   DMA_MST_CTRL_REUSE                   BIT(27)
+#define   DMA_MST_CTRL_BURST_1                 (2 << 24)
+#define   DMA_MST_CTRL_BURST_4                 (3 << 24)
+#define   DMA_MST_CTRL_BURST_8                 (4 << 24)
+#define   DMA_MST_CTRL_BURST_16                        (5 << 24)
+#define   DMA_MST_CTRL_IS_DONE                 BIT(20)
+#define   DMA_MST_CTRL_EN_A                    BIT(2)
+#define   DMA_MST_CTRL_EN_B                    BIT(1)
+
+#define DMA_CFG_A                              0x34
+#define DMA_CFG_B                              0x38
+
+#define FIFO_CTRL                              0x3c
+#define   FIFO_CTRL_CLR_ALL                    BIT(3)
+
+#define DATA_PTR                               0x40
+#define TAG_PTR                                        0x44
+#define ECC_PTR                                        0x48
+
+#define DEC_STATUS                             0x4c
+#define   DEC_STATUS_A_ECC_FAIL                        BIT(1)
+#define   DEC_STATUS_ERR_COUNT_MASK            0x00ff0000
+#define   DEC_STATUS_ERR_COUNT_SHIFT           16
+
+#define HWSTATUS_CMD                           0x50
+#define HWSTATUS_MASK                          0x54
+#define   HWSTATUS_RDSTATUS_MASK(x)            (((x) & 0xff) << 24)
+#define   HWSTATUS_RDSTATUS_VALUE(x)           (((x) & 0xff) << 16)
+#define   HWSTATUS_RBSY_MASK(x)                        (((x) & 0xff) << 8)
+#define   HWSTATUS_RBSY_VALUE(x)               (((x) & 0xff) << 0)
+
+#define BCH_CONFIG                             0xcc
+#define   BCH_ENABLE                           BIT(0)
+#define   BCH_TVAL_4                           (0 << 4)
+#define   BCH_TVAL_8                           (1 << 4)
+#define   BCH_TVAL_14                          (2 << 4)
+#define   BCH_TVAL_16                          (3 << 4)
+
+#define DEC_STAT_RESULT                                0xd0
+#define DEC_STAT_BUF                           0xd4
+#define   DEC_STAT_BUF_FAIL_SEC_FLAG_MASK      0xff000000
+#define   DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT     24
+#define   DEC_STAT_BUF_CORR_SEC_FLAG_MASK      0x00ff0000
+#define   DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT     16
+#define   DEC_STAT_BUF_MAX_CORR_CNT_MASK       0x00001f00
+#define   DEC_STAT_BUF_MAX_CORR_CNT_SHIFT      8
+
+#define OFFSET(val, off)       ((val) < (off) ? 0 : (val) - (off))
+
+#define SKIP_SPARE_BYTES       4
+#define BITS_PER_STEP_RS       18
+#define BITS_PER_STEP_BCH      13
+
+#define INT_MASK               (IER_UND | IER_OVR | IER_CMD_DONE | IER_GIE)
+#define HWSTATUS_CMD_DEFAULT   NAND_STATUS_READY
+#define HWSTATUS_MASK_DEFAULT  (HWSTATUS_RDSTATUS_MASK(1) | \
+                               HWSTATUS_RDSTATUS_VALUE(0) | \
+                               HWSTATUS_RBSY_MASK(NAND_STATUS_READY) | \
+                               HWSTATUS_RBSY_VALUE(NAND_STATUS_READY))
+
+struct tegra_nand_controller {
+       struct nand_hw_control controller;
+       struct device *dev;
+       void __iomem *regs;
+       int irq;
+       struct clk *clk;
+       struct completion command_complete;
+       struct completion dma_complete;
+       bool last_read_error;
+       int cur_cs;
+       struct nand_chip *chip;
+};
+
+struct tegra_nand_chip {
+       struct nand_chip chip;
+       struct gpio_desc *wp_gpio;
+       struct mtd_oob_region ecc;
+       u32 config;
+       u32 config_ecc;
+       u32 bch_config;
+       int cs[1];
+};
+
+static inline struct tegra_nand_controller *
+                       to_tegra_ctrl(struct nand_hw_control *hw_ctrl)
+{
+       return container_of(hw_ctrl, struct tegra_nand_controller, controller);
+}
+
+static inline struct tegra_nand_chip *to_tegra_chip(struct nand_chip *chip)
+{
+       return container_of(chip, struct tegra_nand_chip, chip);
+}
+
+static int tegra_nand_ooblayout_rs_ecc(struct mtd_info *mtd, int section,
+                                      struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_RS * chip->ecc.strength,
+                                         BITS_PER_BYTE);
+
+       if (section > 0)
+               return -ERANGE;
+
+       oobregion->offset = SKIP_SPARE_BYTES;
+       oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
+
+       return 0;
+}
+
+static int tegra_nand_ooblayout_no_free(struct mtd_info *mtd, int section,
+                                       struct mtd_oob_region *oobregion)
+{
+       return -ERANGE;
+}
+
+static const struct mtd_ooblayout_ops tegra_nand_oob_rs_ops = {
+       .ecc = tegra_nand_ooblayout_rs_ecc,
+       .free = tegra_nand_ooblayout_no_free,
+};
+
+static int tegra_nand_ooblayout_bch_ecc(struct mtd_info *mtd, int section,
+                                       struct mtd_oob_region *oobregion)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       int bytes_per_step = DIV_ROUND_UP(BITS_PER_STEP_BCH * chip->ecc.strength,
+                                         BITS_PER_BYTE);
+
+       if (section > 0)
+               return -ERANGE;
+
+       oobregion->offset = SKIP_SPARE_BYTES;
+       oobregion->length = round_up(bytes_per_step * chip->ecc.steps, 4);
+
+       return 0;
+}
+
+static const struct mtd_ooblayout_ops tegra_nand_oob_bch_ops = {
+       .ecc = tegra_nand_ooblayout_bch_ecc,
+       .free = tegra_nand_ooblayout_no_free,
+};
+
+static irqreturn_t tegra_nand_irq(int irq, void *data)
+{
+       struct tegra_nand_controller *ctrl = data;
+       u32 isr, dma;
+
+       isr = readl_relaxed(ctrl->regs + ISR);
+       dma = readl_relaxed(ctrl->regs + DMA_MST_CTRL);
+       dev_dbg(ctrl->dev, "isr %08x\n", isr);
+
+       if (!isr && !(dma & DMA_MST_CTRL_IS_DONE))
+               return IRQ_NONE;
+
+       /*
+        * The bit name is somewhat missleading: This is also set when
+        * HW ECC was successful. The data sheet states:
+        * Correctable OR Un-correctable errors occurred in the DMA transfer...
+        */
+       if (isr & ISR_CORRFAIL_ERR)
+               ctrl->last_read_error = true;
+
+       if (isr & ISR_CMD_DONE)
+               complete(&ctrl->command_complete);
+
+       if (isr & ISR_UND)
+               dev_err(ctrl->dev, "FIFO underrun\n");
+
+       if (isr & ISR_OVR)
+               dev_err(ctrl->dev, "FIFO overrun\n");
+
+       /* handle DMA interrupts */
+       if (dma & DMA_MST_CTRL_IS_DONE) {
+               writel_relaxed(dma, ctrl->regs + DMA_MST_CTRL);
+               complete(&ctrl->dma_complete);
+       }
+
+       /* clear interrupts */
+       writel_relaxed(isr, ctrl->regs + ISR);
+
+       return IRQ_HANDLED;
+}
+
+static const char * const tegra_nand_reg_names[] = {
+       "COMMAND",
+       "STATUS",
+       "ISR",
+       "IER",
+       "CONFIG",
+       "TIMING",
+       NULL,
+       "TIMING2",
+       "CMD_REG1",
+       "CMD_REG2",
+       "ADDR_REG1",
+       "ADDR_REG2",
+       "DMA_MST_CTRL",
+       "DMA_CFG_A",
+       "DMA_CFG_B",
+       "FIFO_CTRL",
+};
+
+static void tegra_nand_dump_reg(struct tegra_nand_controller *ctrl)
+{
+       u32 reg;
+       int i;
+
+       dev_err(ctrl->dev, "Tegra NAND controller register dump\n");
+       for (i = 0; i < ARRAY_SIZE(tegra_nand_reg_names); i++) {
+               const char *reg_name = tegra_nand_reg_names[i];
+
+               if (!reg_name)
+                       continue;
+
+               reg = readl_relaxed(ctrl->regs + (i * 4));
+               dev_err(ctrl->dev, "%s: 0x%08x\n", reg_name, reg);
+       }
+}
+
+static void tegra_nand_controller_abort(struct tegra_nand_controller *ctrl)
+{
+       u32 isr, dma;
+
+       disable_irq(ctrl->irq);
+
+       /* Abort current command/DMA operation */
+       writel_relaxed(0, ctrl->regs + DMA_MST_CTRL);
+       writel_relaxed(0, ctrl->regs + COMMAND);
+
+       /* clear interrupts */
+       isr = readl_relaxed(ctrl->regs + ISR);
+       writel_relaxed(isr, ctrl->regs + ISR);
+       dma = readl_relaxed(ctrl->regs + DMA_MST_CTRL);
+       writel_relaxed(dma, ctrl->regs + DMA_MST_CTRL);
+
+       reinit_completion(&ctrl->command_complete);
+       reinit_completion(&ctrl->dma_complete);
+
+       enable_irq(ctrl->irq);
+}
+
+static int tegra_nand_cmd(struct nand_chip *chip,
+                         const struct nand_subop *subop)
+{
+       const struct nand_op_instr *instr;
+       const struct nand_op_instr *instr_data_in = NULL;
+       struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
+       unsigned int op_id, size = 0, offset = 0;
+       bool first_cmd = true;
+       u32 reg, cmd = 0;
+       int ret;
+
+       for (op_id = 0; op_id < subop->ninstrs; op_id++) {
+               unsigned int naddrs, i;
+               const u8 *addrs;
+               u32 addr1 = 0, addr2 = 0;
+
+               instr = &subop->instrs[op_id];
+
+               switch (instr->type) {
+               case NAND_OP_CMD_INSTR:
+                       if (first_cmd) {
+                               cmd |= COMMAND_CLE;
+                               writel_relaxed(instr->ctx.cmd.opcode,
+                                              ctrl->regs + CMD_REG1);
+                       } else {
+                               cmd |= COMMAND_SEC_CMD;
+                               writel_relaxed(instr->ctx.cmd.opcode,
+                                              ctrl->regs + CMD_REG2);
+                       }
+                       first_cmd = false;
+                       break;
+
+               case NAND_OP_ADDR_INSTR:
+                       offset = nand_subop_get_addr_start_off(subop, op_id);
+                       naddrs = nand_subop_get_num_addr_cyc(subop, op_id);
+                       addrs = &instr->ctx.addr.addrs[offset];
+
+                       cmd |= COMMAND_ALE | COMMAND_ALE_SIZE(naddrs);
+                       for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
+                               addr1 |= *addrs++ << (BITS_PER_BYTE * i);
+                       naddrs -= i;
+                       for (i = 0; i < min_t(unsigned int, 4, naddrs); i++)
+                               addr2 |= *addrs++ << (BITS_PER_BYTE * i);
+
+                       writel_relaxed(addr1, ctrl->regs + ADDR_REG1);
+                       writel_relaxed(addr2, ctrl->regs + ADDR_REG2);
+                       break;
+
+               case NAND_OP_DATA_IN_INSTR:
+                       size = nand_subop_get_data_len(subop, op_id);
+                       offset = nand_subop_get_data_start_off(subop, op_id);
+
+                       cmd |= COMMAND_TRANS_SIZE(size) | COMMAND_PIO |
+                               COMMAND_RX | COMMAND_A_VALID;
+
+                       instr_data_in = instr;
+                       break;
+
+               case NAND_OP_DATA_OUT_INSTR:
+                       size = nand_subop_get_data_len(subop, op_id);
+                       offset = nand_subop_get_data_start_off(subop, op_id);
+
+                       cmd |= COMMAND_TRANS_SIZE(size) | COMMAND_PIO |
+                               COMMAND_TX | COMMAND_A_VALID;
+                       memcpy(&reg, instr->ctx.data.buf.out + offset, size);
+
+                       writel_relaxed(reg, ctrl->regs + RESP);
+                       break;
+
+               case NAND_OP_WAITRDY_INSTR:
+                       cmd |= COMMAND_RBSY_CHK;
+                       break;
+               }
+       }
+
+       cmd |= COMMAND_GO | COMMAND_CE(ctrl->cur_cs);
+       writel_relaxed(cmd, ctrl->regs + COMMAND);
+       ret = wait_for_completion_timeout(&ctrl->command_complete,
+                                         msecs_to_jiffies(500));
+       if (!ret) {
+               dev_err(ctrl->dev, "COMMAND timeout\n");
+               tegra_nand_dump_reg(ctrl);
+               tegra_nand_controller_abort(ctrl);
+               return -ETIMEDOUT;
+       }
+
+       if (instr_data_in) {
+               reg = readl_relaxed(ctrl->regs + RESP);
+               memcpy(instr_data_in->ctx.data.buf.in + offset, &reg, size);
+       }
+
+       return 0;
+}
+
+static const struct nand_op_parser tegra_nand_op_parser = NAND_OP_PARSER(
+       NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
+               NAND_OP_PARSER_PAT_CMD_ELEM(true),
+               NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
+               NAND_OP_PARSER_PAT_CMD_ELEM(true),
+               NAND_OP_PARSER_PAT_WAITRDY_ELEM(true)),
+       NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
+               NAND_OP_PARSER_PAT_DATA_OUT_ELEM(false, 4)),
+       NAND_OP_PARSER_PATTERN(tegra_nand_cmd,
+               NAND_OP_PARSER_PAT_CMD_ELEM(true),
+               NAND_OP_PARSER_PAT_ADDR_ELEM(true, 8),
+               NAND_OP_PARSER_PAT_CMD_ELEM(true),
+               NAND_OP_PARSER_PAT_WAITRDY_ELEM(true),
+               NAND_OP_PARSER_PAT_DATA_IN_ELEM(true, 4)),
+       );
+
+static int tegra_nand_exec_op(struct nand_chip *chip,
+                             const struct nand_operation *op,
+                             bool check_only)
+{
+       return nand_op_parser_exec_op(chip, &tegra_nand_op_parser, op,
+                                     check_only);
+}
+
+static void tegra_nand_select_chip(struct mtd_info *mtd, int die_nr)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct tegra_nand_chip *nand = to_tegra_chip(chip);
+       struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
+
+       if (die_nr < 0 || die_nr > 1) {
+               ctrl->cur_cs = -1;
+               return;
+       }
+
+       ctrl->cur_cs = nand->cs[die_nr];
+}
+
+static void tegra_nand_hw_ecc(struct tegra_nand_controller *ctrl,
+                             struct nand_chip *chip, bool enable)
+{
+       struct tegra_nand_chip *nand = to_tegra_chip(chip);
+
+       if (chip->ecc.algo == NAND_ECC_BCH && enable)
+               writel_relaxed(nand->bch_config, ctrl->regs + BCH_CONFIG);
+       else
+               writel_relaxed(0, ctrl->regs + BCH_CONFIG);
+
+       if (enable)
+               writel_relaxed(nand->config_ecc, ctrl->regs + CONFIG);
+       else
+               writel_relaxed(nand->config, ctrl->regs + CONFIG);
+}
+
+static int tegra_nand_page_xfer(struct mtd_info *mtd, struct nand_chip *chip,
+                               void *buf, void *oob_buf, int oob_len, int page,
+                               bool read)
+{
+       struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
+       enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
+       dma_addr_t dma_addr = 0, dma_addr_oob = 0;
+       u32 addr1, cmd, dma_ctrl;
+       int ret;
+
+       if (read) {
+               writel_relaxed(NAND_CMD_READ0, ctrl->regs + CMD_REG1);
+               writel_relaxed(NAND_CMD_READSTART, ctrl->regs + CMD_REG2);
+       } else {
+               writel_relaxed(NAND_CMD_SEQIN, ctrl->regs + CMD_REG1);
+               writel_relaxed(NAND_CMD_PAGEPROG, ctrl->regs + CMD_REG2);
+       }
+       cmd = COMMAND_CLE | COMMAND_SEC_CMD;
+
+       /* Lower 16-bits are column, by default 0 */
+       addr1 = page << 16;
+
+       if (!buf)
+               addr1 |= mtd->writesize;
+       writel_relaxed(addr1, ctrl->regs + ADDR_REG1);
+
+       if (chip->options & NAND_ROW_ADDR_3) {
+               writel_relaxed(page >> 16, ctrl->regs + ADDR_REG2);
+               cmd |= COMMAND_ALE | COMMAND_ALE_SIZE(5);
+       } else {
+               cmd |= COMMAND_ALE | COMMAND_ALE_SIZE(4);
+       }
+
+       if (buf) {
+               dma_addr = dma_map_single(ctrl->dev, buf, mtd->writesize, dir);
+               ret = dma_mapping_error(ctrl->dev, dma_addr);
+               if (ret) {
+                       dev_err(ctrl->dev, "dma mapping error\n");
+                       return -EINVAL;
+               }
+
+               writel_relaxed(mtd->writesize - 1, ctrl->regs + DMA_CFG_A);
+               writel_relaxed(dma_addr, ctrl->regs + DATA_PTR);
+       }
+
+       if (oob_buf) {
+               dma_addr_oob = dma_map_single(ctrl->dev, oob_buf, mtd->oobsize,
+                                             dir);
+               ret = dma_mapping_error(ctrl->dev, dma_addr_oob);
+               if (ret) {
+                       dev_err(ctrl->dev, "dma mapping error\n");
+                       ret = -EINVAL;
+                       goto err_unmap_dma_page;
+               }
+
+               writel_relaxed(oob_len - 1, ctrl->regs + DMA_CFG_B);
+               writel_relaxed(dma_addr_oob, ctrl->regs + TAG_PTR);
+       }
+
+       dma_ctrl = DMA_MST_CTRL_GO | DMA_MST_CTRL_PERF_EN |
+                  DMA_MST_CTRL_IE_DONE | DMA_MST_CTRL_IS_DONE |
+                  DMA_MST_CTRL_BURST_16;
+
+       if (buf)
+               dma_ctrl |= DMA_MST_CTRL_EN_A;
+       if (oob_buf)
+               dma_ctrl |= DMA_MST_CTRL_EN_B;
+
+       if (read)
+               dma_ctrl |= DMA_MST_CTRL_IN | DMA_MST_CTRL_REUSE;
+       else
+               dma_ctrl |= DMA_MST_CTRL_OUT;
+
+       writel_relaxed(dma_ctrl, ctrl->regs + DMA_MST_CTRL);
+
+       cmd |= COMMAND_GO | COMMAND_RBSY_CHK | COMMAND_TRANS_SIZE(9) |
+              COMMAND_CE(ctrl->cur_cs);
+
+       if (buf)
+               cmd |= COMMAND_A_VALID;
+       if (oob_buf)
+               cmd |= COMMAND_B_VALID;
+
+       if (read)
+               cmd |= COMMAND_RX;
+       else
+               cmd |= COMMAND_TX | COMMAND_AFT_DAT;
+
+       writel_relaxed(cmd, ctrl->regs + COMMAND);
+
+       ret = wait_for_completion_timeout(&ctrl->command_complete,
+                                         msecs_to_jiffies(500));
+       if (!ret) {
+               dev_err(ctrl->dev, "COMMAND timeout\n");
+               tegra_nand_dump_reg(ctrl);
+               tegra_nand_controller_abort(ctrl);
+               ret = -ETIMEDOUT;
+               goto err_unmap_dma;
+       }
+
+       ret = wait_for_completion_timeout(&ctrl->dma_complete,
+                                         msecs_to_jiffies(500));
+       if (!ret) {
+               dev_err(ctrl->dev, "DMA timeout\n");
+               tegra_nand_dump_reg(ctrl);
+               tegra_nand_controller_abort(ctrl);
+               ret = -ETIMEDOUT;
+               goto err_unmap_dma;
+       }
+       ret = 0;
+
+err_unmap_dma:
+       if (oob_buf)
+               dma_unmap_single(ctrl->dev, dma_addr_oob, mtd->oobsize, dir);
+err_unmap_dma_page:
+       if (buf)
+               dma_unmap_single(ctrl->dev, dma_addr, mtd->writesize, dir);
+
+       return ret;
+}
+
+static int tegra_nand_read_page_raw(struct mtd_info *mtd,
+                                   struct nand_chip *chip, u8 *buf,
+                                   int oob_required, int page)
+{
+       void *oob_buf = oob_required ? chip->oob_poi : NULL;
+
+       return tegra_nand_page_xfer(mtd, chip, buf, oob_buf,
+                                   mtd->oobsize, page, true);
+}
+
+static int tegra_nand_write_page_raw(struct mtd_info *mtd,
+                                    struct nand_chip *chip, const u8 *buf,
+                                    int oob_required, int page)
+{
+       void *oob_buf = oob_required ? chip->oob_poi : NULL;
+
+       return tegra_nand_page_xfer(mtd, chip, (void *)buf, oob_buf,
+                                    mtd->oobsize, page, false);
+}
+
+static int tegra_nand_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
+                              int page)
+{
+       return tegra_nand_page_xfer(mtd, chip, NULL, chip->oob_poi,
+                                   mtd->oobsize, page, true);
+}
+
+static int tegra_nand_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
+                               int page)
+{
+       return tegra_nand_page_xfer(mtd, chip, NULL, chip->oob_poi,
+                                   mtd->oobsize, page, false);
+}
+
+static int tegra_nand_read_page_hwecc(struct mtd_info *mtd,
+                                     struct nand_chip *chip, u8 *buf,
+                                     int oob_required, int page)
+{
+       struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
+       struct tegra_nand_chip *nand = to_tegra_chip(chip);
+       void *oob_buf = oob_required ? chip->oob_poi : NULL;
+       u32 dec_stat, max_corr_cnt;
+       unsigned long fail_sec_flag;
+       int ret;
+
+       tegra_nand_hw_ecc(ctrl, chip, true);
+       ret = tegra_nand_page_xfer(mtd, chip, buf, oob_buf, 0, page, true);
+       tegra_nand_hw_ecc(ctrl, chip, false);
+       if (ret)
+               return ret;
+
+       /* No correctable or un-correctable errors, page must have 0 bitflips */
+       if (!ctrl->last_read_error)
+               return 0;
+
+       /*
+        * Correctable or un-correctable errors occurred. Use DEC_STAT_BUF
+        * which contains information for all ECC selections.
+        *
+        * Note that since we do not use Command Queues DEC_RESULT does not
+        * state the number of pages we can read from the DEC_STAT_BUF. But
+        * since CORRFAIL_ERR did occur during page read we do have a valid
+        * result in DEC_STAT_BUF.
+        */
+       ctrl->last_read_error = false;
+       dec_stat = readl_relaxed(ctrl->regs + DEC_STAT_BUF);
+
+       fail_sec_flag = (dec_stat & DEC_STAT_BUF_FAIL_SEC_FLAG_MASK) >>
+                       DEC_STAT_BUF_FAIL_SEC_FLAG_SHIFT;
+
+       max_corr_cnt = (dec_stat & DEC_STAT_BUF_MAX_CORR_CNT_MASK) >>
+                      DEC_STAT_BUF_MAX_CORR_CNT_SHIFT;
+
+       if (fail_sec_flag) {
+               int bit, max_bitflips = 0;
+
+               /*
+                * Since we do not support subpage writes, a complete page
+                * is either written or not. We can take a shortcut here by
+                * checking wheather any of the sector has been successful
+                * read. If at least one sectors has been read successfully,
+                * the page must have been a written previously. It cannot
+                * be an erased page.
+                *
+                * E.g. controller might return fail_sec_flag with 0x4, which
+                * would mean only the third sector failed to correct. The
+                * page must have been written and the third sector is really
+                * not correctable anymore.
+                */
+               if (fail_sec_flag ^ GENMASK(chip->ecc.steps - 1, 0)) {
+                       mtd->ecc_stats.failed += hweight8(fail_sec_flag);
+                       return max_corr_cnt;
+               }
+
+               /*
+                * All sectors failed to correct, but the ECC isn't smart
+                * enough to figure out if a page is really just erased.
+                * Read OOB data and check whether data/OOB is completely
+                * erased or if error correction just failed for all sub-
+                * pages.
+                */
+               ret = tegra_nand_read_oob(mtd, chip, page);
+               if (ret < 0)
+                       return ret;
+
+               for_each_set_bit(bit, &fail_sec_flag, chip->ecc.steps) {
+                       u8 *data = buf + (chip->ecc.size * bit);
+                       u8 *oob = chip->oob_poi + nand->ecc.offset +
+                                 (chip->ecc.bytes * bit);
+
+                       ret = nand_check_erased_ecc_chunk(data, chip->ecc.size,
+                                                         oob, chip->ecc.bytes,
+                                                         NULL, 0,
+                                                         chip->ecc.strength);
+                       if (ret < 0) {
+                               mtd->ecc_stats.failed++;
+                       } else {
+                               mtd->ecc_stats.corrected += ret;
+                               max_bitflips = max(ret, max_bitflips);
+                       }
+               }
+
+               return max_t(unsigned int, max_corr_cnt, max_bitflips);
+       } else {
+               int corr_sec_flag;
+
+               corr_sec_flag = (dec_stat & DEC_STAT_BUF_CORR_SEC_FLAG_MASK) >>
+                               DEC_STAT_BUF_CORR_SEC_FLAG_SHIFT;
+
+               /*
+                * The value returned in the register is the maximum of
+                * bitflips encountered in any of the ECC regions. As there is
+                * no way to get the number of bitflips in a specific regions
+                * we are not able to deliver correct stats but instead
+                * overestimate the number of corrected bitflips by assuming
+                * that all regions where errors have been corrected
+                * encountered the maximum number of bitflips.
+                */
+               mtd->ecc_stats.corrected += max_corr_cnt * hweight8(corr_sec_flag);
+
+               return max_corr_cnt;
+       }
+}
+
+static int tegra_nand_write_page_hwecc(struct mtd_info *mtd,
+                                      struct nand_chip *chip, const u8 *buf,
+                                      int oob_required, int page)
+{
+       struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
+       void *oob_buf = oob_required ? chip->oob_poi : NULL;
+       int ret;
+
+       tegra_nand_hw_ecc(ctrl, chip, true);
+       ret = tegra_nand_page_xfer(mtd, chip, (void *)buf, oob_buf,
+                                  0, page, false);
+       tegra_nand_hw_ecc(ctrl, chip, false);
+
+       return ret;
+}
+
+static void tegra_nand_setup_timing(struct tegra_nand_controller *ctrl,
+                                   const struct nand_sdr_timings *timings)
+{
+       /*
+        * The period (and all other timings in this function) is in ps,
+        * so need to take care here to avoid integer overflows.
+        */
+       unsigned int rate = clk_get_rate(ctrl->clk) / 1000000;
+       unsigned int period = DIV_ROUND_UP(1000000, rate);
+       u32 val, reg = 0;
+
+       val = DIV_ROUND_UP(max3(timings->tAR_min, timings->tRR_min,
+                               timings->tRC_min), period);
+       reg |= TIMING_TCR_TAR_TRR(OFFSET(val, 3));
+
+       val = DIV_ROUND_UP(max(max(timings->tCS_min, timings->tCH_min),
+                              max(timings->tALS_min, timings->tALH_min)),
+                          period);
+       reg |= TIMING_TCS(OFFSET(val, 2));
+
+       val = DIV_ROUND_UP(max(timings->tRP_min, timings->tREA_max) + 6000,
+                          period);
+       reg |= TIMING_TRP(OFFSET(val, 1)) | TIMING_TRP_RESP(OFFSET(val, 1));
+
+       reg |= TIMING_TWB(OFFSET(DIV_ROUND_UP(timings->tWB_max, period), 1));
+       reg |= TIMING_TWHR(OFFSET(DIV_ROUND_UP(timings->tWHR_min, period), 1));
+       reg |= TIMING_TWH(OFFSET(DIV_ROUND_UP(timings->tWH_min, period), 1));
+       reg |= TIMING_TWP(OFFSET(DIV_ROUND_UP(timings->tWP_min, period), 1));
+       reg |= TIMING_TRH(OFFSET(DIV_ROUND_UP(timings->tREH_min, period), 1));
+
+       writel_relaxed(reg, ctrl->regs + TIMING_1);
+
+       val = DIV_ROUND_UP(timings->tADL_min, period);
+       reg = TIMING_TADL(OFFSET(val, 3));
+
+       writel_relaxed(reg, ctrl->regs + TIMING_2);
+}
+
+static int tegra_nand_setup_data_interface(struct mtd_info *mtd, int csline,
+                                       const struct nand_data_interface *conf)
+{
+       struct nand_chip *chip = mtd_to_nand(mtd);
+       struct tegra_nand_controller *ctrl = to_tegra_ctrl(chip->controller);
+       const struct nand_sdr_timings *timings;
+
+       timings = nand_get_sdr_timings(conf);
+       if (IS_ERR(timings))
+               return PTR_ERR(timings);
+
+       if (csline == NAND_DATA_IFACE_CHECK_ONLY)
+               return 0;
+
+       tegra_nand_setup_timing(ctrl, timings);
+
+       return 0;
+}
+
+static const int rs_strength_bootable[] = { 4 };
+static const int rs_strength[] = { 4, 6, 8 };
+static const int bch_strength_bootable[] = { 8, 16 };
+static const int bch_strength[] = { 4, 8, 14, 16 };
+
+static int tegra_nand_get_strength(struct nand_chip *chip, const int *strength,
+                                  int strength_len, int bits_per_step,
+                                  int oobsize)
+{
+       bool maximize = chip->ecc.options & NAND_ECC_MAXIMIZE;
+       int i;
+
+       /*
+        * Loop through available strengths. Backwards in case we try to
+        * maximize the BCH strength.
+        */
+       for (i = 0; i < strength_len; i++) {
+               int strength_sel, bytes_per_step, bytes_per_page;
+
+               if (maximize) {
+                       strength_sel = strength[strength_len - i - 1];
+               } else {
+                       strength_sel = strength[i];
+
+                       if (strength_sel < chip->ecc_strength_ds)
+                               continue;
+               }
+
+               bytes_per_step = DIV_ROUND_UP(bits_per_step * strength_sel,
+                                             BITS_PER_BYTE);
+               bytes_per_page = round_up(bytes_per_step * chip->ecc.steps, 4);
+
+               /* Check whether strength fits OOB */
+               if (bytes_per_page < (oobsize - SKIP_SPARE_BYTES))
+                       return strength_sel;
+       }
+
+       return -EINVAL;
+}
+
+static int tegra_nand_select_strength(struct nand_chip *chip, int oobsize)
+{
+       const int *strength;
+       int strength_len, bits_per_step;
+
+       switch (chip->ecc.algo) {
+       case NAND_ECC_RS:
+               bits_per_step = BITS_PER_STEP_RS;
+               if (chip->options & NAND_IS_BOOT_MEDIUM) {
+                       strength = rs_strength_bootable;
+                       strength_len = ARRAY_SIZE(rs_strength_bootable);
+               } else {
+                       strength = rs_strength;
+                       strength_len = ARRAY_SIZE(rs_strength);
+               }
+               break;
+       case NAND_ECC_BCH:
+               bits_per_step = BITS_PER_STEP_BCH;
+               if (chip->options & NAND_IS_BOOT_MEDIUM) {
+                       strength = bch_strength_bootable;
+                       strength_len = ARRAY_SIZE(bch_strength_bootable);
+               } else {
+                       strength = bch_strength;
+                       strength_len = ARRAY_SIZE(bch_strength);
+               }
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       return tegra_nand_get_strength(chip, strength, strength_len,
+                                      bits_per_step, oobsize);
+}
+
+static int tegra_nand_chips_init(struct device *dev,
+                                struct tegra_nand_controller *ctrl)
+{
+       struct device_node *np = dev->of_node;
+       struct device_node *np_nand;
+       int nsels, nchips = of_get_child_count(np);
+       struct tegra_nand_chip *nand;
+       struct mtd_info *mtd;
+       struct nand_chip *chip;
+       int bits_per_step;
+       int ret;
+       u32 cs;
+
+       if (nchips != 1) {
+               dev_err(dev, "Currently only one NAND chip supported\n");
+               return -EINVAL;
+       }
+
+       np_nand = of_get_next_child(np, NULL);
+
+       nsels = of_property_count_elems_of_size(np_nand, "reg", sizeof(u32));
+       if (nsels != 1) {
+               dev_err(dev, "Missing/invalid reg property\n");
+               return -EINVAL;
+       }
+
+       /* Retrieve CS id, currently only single die NAND supported */
+       ret = of_property_read_u32(np_nand, "reg", &cs);
+       if (ret) {
+               dev_err(dev, "could not retrieve reg property: %d\n", ret);
+               return ret;
+       }
+
+       nand = devm_kzalloc(dev, sizeof(*nand), GFP_KERNEL);
+       if (!nand)
+               return -ENOMEM;
+
+       nand->cs[0] = cs;
+
+       nand->wp_gpio = devm_gpiod_get_optional(dev, "wp", GPIOD_OUT_LOW);
+
+       if (IS_ERR(nand->wp_gpio)) {
+               ret = PTR_ERR(nand->wp_gpio);
+               dev_err(dev, "Failed to request WP GPIO: %d\n", ret);
+               return ret;
+       }
+
+       chip = &nand->chip;
+       chip->controller = &ctrl->controller;
+
+       mtd = nand_to_mtd(chip);
+
+       mtd->dev.parent = dev;
+       mtd->owner = THIS_MODULE;
+
+       nand_set_flash_node(chip, np_nand);
+
+       if (!mtd->name)
+               mtd->name = "tegra_nand";
+
+       chip->options = NAND_NO_SUBPAGE_WRITE | NAND_USE_BOUNCE_BUFFER;
+       chip->exec_op = tegra_nand_exec_op;
+       chip->select_chip = tegra_nand_select_chip;
+       chip->setup_data_interface = tegra_nand_setup_data_interface;
+
+       ret = nand_scan_ident(mtd, 1, NULL);
+       if (ret)
+               return ret;
+
+       if (chip->bbt_options & NAND_BBT_USE_FLASH)
+               chip->bbt_options |= NAND_BBT_NO_OOB;
+
+       chip->ecc.mode = NAND_ECC_HW;
+       chip->ecc.size = 512;
+       chip->ecc.steps = mtd->writesize / chip->ecc.size;
+       if (chip->ecc_step_ds != 512) {
+               dev_err(dev, "Unsupported step size %d\n", chip->ecc_step_ds);
+               return -EINVAL;
+       }
+
+       chip->ecc.read_page = tegra_nand_read_page_hwecc;
+       chip->ecc.write_page = tegra_nand_write_page_hwecc;
+       chip->ecc.read_page_raw = tegra_nand_read_page_raw;
+       chip->ecc.write_page_raw = tegra_nand_write_page_raw;
+       chip->ecc.read_oob = tegra_nand_read_oob;
+       chip->ecc.write_oob = tegra_nand_write_oob;
+
+       if (chip->options & NAND_BUSWIDTH_16)
+               nand->config |= CONFIG_BUS_WIDTH_16;
+
+       if (chip->ecc.algo == NAND_ECC_UNKNOWN) {
+               if (mtd->writesize < 2048)
+                       chip->ecc.algo = NAND_ECC_RS;
+               else
+                       chip->ecc.algo = NAND_ECC_BCH;
+       }
+
+       if (chip->ecc.algo == NAND_ECC_BCH && mtd->writesize < 2048) {
+               dev_err(dev, "BCH supports 2K or 4K page size only\n");
+               return -EINVAL;
+       }
+
+       if (!chip->ecc.strength) {
+               ret = tegra_nand_select_strength(chip, mtd->oobsize);
+               if (ret < 0) {
+                       dev_err(dev, "No valid strength found, minimum %d\n",
+                               chip->ecc_strength_ds);
+                       return ret;
+               }
+
+               chip->ecc.strength = ret;
+       }
+
+       nand->config_ecc = CONFIG_PIPE_EN | CONFIG_SKIP_SPARE |
+                          CONFIG_SKIP_SPARE_SIZE_4;
+
+       switch (chip->ecc.algo) {
+       case NAND_ECC_RS:
+               bits_per_step = BITS_PER_STEP_RS * chip->ecc.strength;
+               mtd_set_ooblayout(mtd, &tegra_nand_oob_rs_ops);
+               nand->config_ecc |= CONFIG_HW_ECC | CONFIG_ECC_SEL |
+                                   CONFIG_ERR_COR;
+               switch (chip->ecc.strength) {
+               case 4:
+                       nand->config_ecc |= CONFIG_TVAL_4;
+                       break;
+               case 6:
+                       nand->config_ecc |= CONFIG_TVAL_6;
+                       break;
+               case 8:
+                       nand->config_ecc |= CONFIG_TVAL_8;
+                       break;
+               default:
+                       dev_err(dev, "ECC strength %d not supported\n",
+                               chip->ecc.strength);
+                       return -EINVAL;
+               }
+               break;
+       case NAND_ECC_BCH:
+               bits_per_step = BITS_PER_STEP_BCH * chip->ecc.strength;
+               mtd_set_ooblayout(mtd, &tegra_nand_oob_bch_ops);
+               nand->bch_config = BCH_ENABLE;
+               switch (chip->ecc.strength) {
+               case 4:
+                       nand->bch_config |= BCH_TVAL_4;
+                       break;
+               case 8:
+                       nand->bch_config |= BCH_TVAL_8;
+                       break;
+               case 14:
+                       nand->bch_config |= BCH_TVAL_14;
+                       break;
+               case 16:
+                       nand->bch_config |= BCH_TVAL_16;
+                       break;
+               default:
+                       dev_err(dev, "ECC strength %d not supported\n",
+                               chip->ecc.strength);
+                       return -EINVAL;
+               }
+               break;
+       default:
+               dev_err(dev, "ECC algorithm not supported\n");
+               return -EINVAL;
+       }
+
+       dev_info(dev, "Using %s with strength %d per 512 byte step\n",
+                chip->ecc.algo == NAND_ECC_BCH ? "BCH" : "RS",
+                chip->ecc.strength);
+
+       chip->ecc.bytes = DIV_ROUND_UP(bits_per_step, BITS_PER_BYTE);
+
+       switch (mtd->writesize) {
+       case 256:
+               nand->config |= CONFIG_PS_256;
+               break;
+       case 512:
+               nand->config |= CONFIG_PS_512;
+               break;
+       case 1024:
+               nand->config |= CONFIG_PS_1024;
+               break;
+       case 2048:
+               nand->config |= CONFIG_PS_2048;
+               break;
+       case 4096:
+               nand->config |= CONFIG_PS_4096;
+               break;
+       default:
+               dev_err(dev, "Unsupported writesize %d\n", mtd->writesize);
+               return -ENODEV;
+       }
+
+       /* Store complete configuration for HW ECC in config_ecc */
+       nand->config_ecc |= nand->config;
+
+       /* Non-HW ECC read/writes complete OOB */
+       nand->config |= CONFIG_TAG_BYTE_SIZE(mtd->oobsize - 1);
+       writel_relaxed(nand->config, ctrl->regs + CONFIG);
+
+       ret = nand_scan_tail(mtd);
+       if (ret)
+               return ret;
+
+       mtd_ooblayout_ecc(mtd, 0, &nand->ecc);
+
+       ret = mtd_device_register(mtd, NULL, 0);
+       if (ret) {
+               dev_err(dev, "Failed to register mtd device: %d\n", ret);
+               nand_cleanup(chip);
+               return ret;
+       }
+
+       ctrl->chip = chip;
+
+       return 0;
+}
+
+static int tegra_nand_probe(struct platform_device *pdev)
+{
+       struct reset_control *rst;
+       struct tegra_nand_controller *ctrl;
+       struct resource *res;
+       int err = 0;
+
+       ctrl = devm_kzalloc(&pdev->dev, sizeof(*ctrl), GFP_KERNEL);
+       if (!ctrl)
+               return -ENOMEM;
+
+       ctrl->dev = &pdev->dev;
+       nand_hw_control_init(&ctrl->controller);
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       ctrl->regs = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(ctrl->regs))
+               return PTR_ERR(ctrl->regs);
+
+       rst = devm_reset_control_get(&pdev->dev, "nand");
+       if (IS_ERR(rst))
+               return PTR_ERR(rst);
+
+       ctrl->clk = devm_clk_get(&pdev->dev, "nand");
+       if (IS_ERR(ctrl->clk))
+               return PTR_ERR(ctrl->clk);
+
+       err = clk_prepare_enable(ctrl->clk);
+       if (err)
+               return err;
+
+       err = reset_control_reset(rst);
+       if (err) {
+               dev_err(ctrl->dev, "Failed to reset HW: %d\n", err);
+               goto err_disable_clk;
+       }
+
+       writel_relaxed(HWSTATUS_CMD_DEFAULT, ctrl->regs + HWSTATUS_CMD);
+       writel_relaxed(HWSTATUS_MASK_DEFAULT, ctrl->regs + HWSTATUS_MASK);
+       writel_relaxed(INT_MASK, ctrl->regs + IER);
+
+       init_completion(&ctrl->command_complete);
+       init_completion(&ctrl->dma_complete);
+
+       ctrl->irq = platform_get_irq(pdev, 0);
+       err = devm_request_irq(&pdev->dev, ctrl->irq, tegra_nand_irq, 0,
+                              dev_name(&pdev->dev), ctrl);
+       if (err) {
+               dev_err(ctrl->dev, "Failed to get IRQ: %d\n", err);
+               goto err_disable_clk;
+       }
+
+       writel_relaxed(DMA_MST_CTRL_IS_DONE, ctrl->regs + DMA_MST_CTRL);
+
+       err = tegra_nand_chips_init(ctrl->dev, ctrl);
+       if (err)
+               goto err_disable_clk;
+
+       platform_set_drvdata(pdev, ctrl);
+
+       return 0;
+
+err_disable_clk:
+       clk_disable_unprepare(ctrl->clk);
+       return err;
+}
+
+static int tegra_nand_remove(struct platform_device *pdev)
+{
+       struct tegra_nand_controller *ctrl = platform_get_drvdata(pdev);
+       struct nand_chip *chip = ctrl->chip;
+       struct mtd_info *mtd = nand_to_mtd(chip);
+       int ret;
+
+       ret = mtd_device_unregister(mtd);
+       if (ret)
+               return ret;
+
+       nand_cleanup(chip);
+
+       clk_disable_unprepare(ctrl->clk);
+
+       return 0;
+}
+
+static const struct of_device_id tegra_nand_of_match[] = {
+       { .compatible = "nvidia,tegra20-nand" },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, tegra_nand_of_match);
+
+static struct platform_driver tegra_nand_driver = {
+       .driver = {
+               .name = "tegra-nand",
+               .of_match_table = tegra_nand_of_match,
+       },
+       .probe = tegra_nand_probe,
+       .remove = tegra_nand_remove,
+};
+module_platform_driver(tegra_nand_driver);
+
+MODULE_DESCRIPTION("NVIDIA Tegra NAND driver");
+MODULE_AUTHOR("Thierry Reding <thierry.reding@nvidia.com>");
+MODULE_AUTHOR("Lucas Stach <dev@lynxeye.de>");
+MODULE_AUTHOR("Stefan Agner <stefan@agner.ch>");
+MODULE_LICENSE("GPL v2");